ah don't sweat it. If you can wrap your head around cell bio and genetics, you can figure out cars. I got my degree in Biology too. I like to give my buddy (automotive mechanical engineer) sh*t about how engineering is the "lesser" of the two sciences...
(J/K, got nothing but for engineers... especially good ones)

... seriously though, you can figure out cars. I learned a lot helping by helping my dad when I was growing up. However, nowadays How Stuff Works has a great automotive section.

As to your question, I have a counter question for you. How many miles does your car have, and when's the last time you had your oil changed?